[10.13] The Steward Observatory NIR Survey of UCHII Regions

We have recently completed the first half of a
near-infrared imaging and spectroscopic survey of 140 radio
selected ultra-compact HII (UCHII) regions using the Steward
Observatory Bok 90" telescope. We detect 75% of the UCHII
regions using 2 micron spectroscopy to identify the hydrogen
Brackett gamma feature. We include a simple nebular analysis
using HeI, H_2, and FeII to probe the conditions within a
few of the UCHII regions. Simultaneous images taken at 1.65
micron show a number of the UCHII regions lie within a
stellar cluster. More recent follow up 2 micron spectra
using the Multiple Mirror Telescope has allowed us to
determine spectroscopic classifications for some of these
stars which may be the ionizing source of the nearby UCHII
region. Our results set important limits on the timescales
for the formation of the most massive stars and gives us an
early glimpse at the local environment within which massive
stars are forming.

The author(s) of this abstract have provided an email address for comments about the abstract: mhanson@as.arizona.edu